Featured Research

Efficient, robust and economic catalyst materials hold the key to achieving a breakthrough in fuel cell technology. Scientists have developed a material for converting hydrogen and oxygen to water using a tenth of the typical amount of platinum that was previously required. With the aid of state-of-the-art electron microscopy, the researchers discovered that the function of the nanometre-scale catalyst particles is decisively determined by their geometric shape and atomic structure.

Share This

This is an electron micrograph and atomistic model (bottom right) of a highly oxygen-activating platinum-nickel catalyst particle. Its diameter is approximately 10,000 times smaller than the diameter of a human hair. Red spheres represent platinum atoms and green spheres represent nickel atoms. One of the properties of such octahedra is that most surface atoms have the same geometric arrangement. The micrograph was taken at the PICO microscope.

Efficient, robust and economic catalyst materials hold the key to achieving a breakthrough in fuel cell technology. Scientists from Jülich and Berlin have developed a material for converting hydrogen and oxygen to water using a tenth of the typical amount of platinum that was previously required. With the aid of state-of-the-art electron microscopy, the researchers discovered that the function of the nanometre-scale catalyst particles is decisively determined by their geometric shape and atomic structure. This discovery opens up new paths for further improving catalysts for energy conversion and storage.

Related Articles

The results have been published in the current issue of the journal Nature Materials.

Hydrogen-powered fuel cells are regarded as a clean alternative to conventional combustion engines, as, aside from electric energy, the only substance produced during operation is water. At present, the implementation of hydrogen fuel cells is being hindered by the high material costs of platinum. Large quantities of the expensive noble metal are still required for the electrodes in the fuel cells at which the chemical conversion processes take place. Without the catalytic effect of the platinum, it is not currently possible to achieve the necessary conversion rates.

As catalysis takes place at the surface of the platinum only, material can be saved and, simultaneously, the efficiency of the electrodes improved by using platinum nanoparticles, thus increasing the ratio of platinum surface to material required. Although the tiny particles are around ten thousand times smaller than the diameter of a human hair, the surface area of a kilogram of such particles is equivalent to that of several football fields.

Still more platinum can be saved by mixing it with other, less valuable metals, such as nickel or copper. Scientists from Forschungszentrum Jülich and Technische Universität Berlin have succeeded in developing efficient metallic catalyst particles for converting hydrogen and oxygen to water using only a tenth of the typical amount of platinum that was previously required.

The new catalyst consists not of the round nanoparticles that were previously in widespread use, but of octrahedral-shaped nanoparticles of a platinum-nickel alloy. The researchers discovered that the unique manner in which the platinum and nickel atoms arrange themselves on the surfaces of these particles serves to optimally accelerate the chemical reaction between hydrogen and oxygen to form water. Round or cubic particles, on the other hand, have different atomic arrangements at the surface and are therefore less effective catalysts for the chemical reaction, something which would have to be compensated by using increased amounts of noble metal.

The way in which the life-cycle of the catalysts depends on and can be optimized by their atomic composition was the subject of the research team's investigation, which made use of ultrahigh-resolution electron microscopy at the Ernst Ruska-Centre (ER-C), a facility of the Jülich Aachen Research Alliance. "A decisive factor for understanding the life-cycle of the catalysts was the observation that nickel and platinum atoms prefer not to be evenly distributed at the surface of the nano-octahedra," explains Dr. Marc Heggen from ER-C and the Peter Grünberg Institute at Forschungszentrum Jülich. "Although this is advantageous for reactivity, it limits lifetime."

To identify the location of each element with atomic precision, the researchers used a method in which the electron beam of one of the world's leading ultrahigh-resolution electron microscopes is finely focused, sent through the specimen and, by interactions with the specimen, loses part of its energy. Each element in the specimen can thus be identified like a fingerprint. Conventional electron microscopes are not capable of detecting such chemical signatures with atomic resolution.

"This pioneering experimental work provides direct evidence for the fact that the choice of the correct geometric shape for the catalyst particles is as important for optimizing their function as the choice of their composition and size," says Prof. Peter Strasser from Technische Universität Berlin. "This provides researchers with new possibilities for further improving functional materials, especially catalysts, for energy storage." The latest experiments from Strasser's research group indicate that substantial increases in efficiency may also be possible for the reaction splitting water to produce oxygen in electrolysers, for which the even more expensive noble metal iridium is used.

More From ScienceDaily

More Matter & Energy News

Featured Research

Mar. 3, 2015 — By examining the forces that the segments of mosquito legs generate against a water surface, researchers have unraveled the mechanical logic that allows the mosquitoes to walk on water, which may ... full story

Mar. 3, 2015 — Researchers have developed a new way of rapidly screening yeasts that could help produce more sustainable biofuels. The new technique could also be a boon in the search for new ways of deriving ... full story

Mar. 3, 2015 — Major cities in the UK are falling behind their international counterparts in terms of their use of smart technologies, according to a new study. The research has found that smart cities in the UK, ... full story

Mar. 3, 2015 — Scientists have explored friction at the microscopic level. They discovered that the force generating friction is much stronger than previously thought. The discovery is an important step toward ... full story

Mar. 3, 2015 — Micro-drones are already being put to use in a large number of areas: These small aircraft face extensive requirements when performing aerial observation tasks or when deployed in the field of ... full story

Mar. 3, 2015 — Recent research contributes to the effort to determine the nature of dark matter, one of the most important mysteries in physics. As indirect evidence provided by its gravitational effects, dark ... full story

Mar. 3, 2015 — Physicists have shown for the first time that electrons in graphene can be moved along a predefined path. This movement occurs entirely without loss and could provide a basis for numerous ... full story

Mar. 3, 2015 — Magnetic vortex structures, so-called skyrmions, could in future store and process information very efficiently. They could also be the basis for high-frequency components. For the first time, a team ... full story

Featured Videos

Forensic Holodeck Creates 3D Crime Scenes

Reuters - Innovations Video Online (Mar. 3, 2015) — A holodeck is no longer the preserve of TV sci-fi classic Star Trek, thanks to researchers from the Institute of Forensic Medicine Zurich, who have created what they say is the first system in the world to visualise the 3D data of forensic scans. Jim Drury saw it in operation.
Video provided by Reuters

Solar Plane Passes New Test Ahead of World Tour

AFP (Mar. 2, 2015) — A solar-powered plane made a third successful test flight in the United Arab Emirates on Monday ahead of a planned round-the-world tour to promote alternative energy. Duration: 01:05
Video provided by AFP

Electric Hydrofoiling Watercraft Delivers Eco-Friendly Thrills

Reuters - Innovations Video Online (Mar. 2, 2015) — The Quadrofoil is a high-tech electric personal watercraft that its makers call a &apos;sports car for the water&apos;. When it hits 10 km/h, the Slovenian-engineered Quadrofoil is lifted above the water onto four wing-like hydrofoils where it &apos;flies&apos; above the surface with minimal water resistance. Matthew Stock reports.
Video provided by Reuters

Related Stories

June 23, 2014 — Hydrogen-oxygen fuel cells are the ultimate clean power-generating device, which extract electric power from hydrogen and oxygen with high efficiency and emit only water as waste. However, there are ... full story

Mar. 31, 2011 — Engineers have created a new fuel cell catalyst system using nanowires made of a novel material that boosts long-term performance by 2.4 times compared to today's technology. The nanowires are ... full story

Aug. 2, 2010 — In the quest for efficient, cost-effective and commercially viable fuel cells, scientists have discovered a catalyst and catalyst-support combination that could make fuel cells more stable, conk-out ... full story

ScienceDaily features breaking news and videos about the latest discoveries in health, technology, the environment, and more -- from major news services and leading universities, scientific journals, and research organizations.